Portable talking motion picture apparatus



Feb, 25, 1936. H. c. HOLDEN PORTABLE TALKING MOTION PICTURE APPARATUS Filed Feb. 12, 1932 9 Sheets-Sheet 1 N E w .7 RH M m g m m .fi w m A a .0% m W////// m Feb. 25, 1936. H. c. HOLDEN PORTABLE TALKING MOTION PICTURE APPARATUS Filed Feb. 12, 1932 9 Sheets-Sheet 2 INVENTOR HAROLD C. HOLDEN BY 1%? ATTORNEY Feb. 25, 1936. H. c. HOLDEN PORTABLE TALKING MOTION PICTURE APPARATUS Filed Feb. 12, 1932 9 Sheets-Sheet 3 INVENTOR HAROLD C. HOLDEN BY g ATTORNEY Feb. 25,1936. H. c. HOLDEN PORTABLE TALKING MOTION PICTURE APPARATUS Fild Feb. 12, 1952 9 Sheets-Sheet 4 Feb. 25, 1936. H. c. HOLDEN PORTABLE TALKING MOTION PICTURE APPARATUS 9 Sheets-Sheet 5 Filed Feb. 12, 1932 INVENTOR HAROLD c. HOLDEN 1 BY HQ 2 ATTORNEY Feb. 25, 1936. H. c. HOLDEN PORTABLE TALKING MOTION PICTURE APPARATUS Filed Feb. 12, 1952 9 Sheets -Shaet 6' HAROLD c. HOLDEN ATTORNEY Feb. 25, 1936. H,'C. HOLDEN PORTABLE TALKING MOTION PICTURE APPARATUS 9 Sheets-Sheet 7 Filed Feb 12, 1932 INVENTOR HAROLD C.HOLDEN BY g ATTORNEY H. c. HOLDEN "2,031,832

PORTABLE TALKING MOTION PICTURE APPARATUS Feb. 25, 1936.

9 Sheets-Sheet 8 Filed Feb. 12, 1932 M Y o u mung R ..0 Ec .H MD A m/ Feb. 25, 1936. H. c. HOLDEN PORTABLE TALKING MOTION PICTURE APPARATUS Fil'ed Feb. 12, 1952 SSheetS-Sheet 9 INVENTOR HAROLD C. HOLDEN BY, ATTORNEY,

Patented Feb. 25, 1 936 The UNITED STATE PORTABLE TALKING MOTION PICTURE APPARATUS Hamid 0. Holden, Philadelphia, Pa, assl Radio Corporation of America, a corpora Delaware s PATENT OFFICE gnor to tion of Application February 12, 1932, Serial No. 592,453 9 Claims. (Cl. 271-23) will be apparent from a reading of the following present invention relates to portable talking motion picture apparatus particularly adapted to provis home and educational use. It involves the ion of an improved projector, an improved on a comm

sound-track of one of the usual types in ercial use.

Another object of the invention is to provide such an apparatus which is capable of high quality sound reproduction from such a film. Another object of the invention is to provide such an apparatus which requires a minimum power to operate it and which can therefore be operated from any ordinary household power supp y. I

Another object of the invention is to provide an extremely compact and rugged combination of motion picture projector, sound reproducer and amplifier.

Another object motion picture of the invention is to provide a projector mechanism which is built into a unitary structure with the driving motor Another object of the sound or sep invention is to provide a reproducer which requires no individual arate drive mechanism.

Another object of the invention is to provide a photocell and quately shielded cally by the remainder of the construction or which is adeboth mechanically and electriamplifier structure the soundhead.

Another object of a prol' no projection operation,

the invention is to provide ector which is so sound-proof as to require booth or the equivalent for its and thereby permit its operation in any desired location such as the midst of the audience.

Another object of the invention is the provision of an improved film gate w ch permits the film to be driven from one row of sprocket holes only without flicker at the aperture and without the film tending to run off Another object of the of a carrying case for permit operation of to one side or the other. invention is the provision the projector adapted to the projector therein and provided with appropriate facilities for ventilation, r

eplacement of amplifier tubes, and the admission and exit of the film and the necessary wires.

er and ancillary objects of the invention specification in connection with the accompanying drawings and its scope will be pointed out in the appended drawings wherein Fig. 1. is a side view of .the projector as mounted in the carrying case and with the carrying case open for threading of the projector,

Fig. 2 is a view of the opposite side of the projector with the amplifier and rectifier tubes removed and with the protocell housing,

cover removed from the Fig. 3 is an elevation corresponding generally to Fig. l and indicating much of the interior construction of the device,

Fig. 4 is a longitudinal section along of the optical system of the sound reproducer,

the axis Fig. 5 is a view partly in section from the lefthand end of Fig. 1 or the righthand end of Fig. 2 showing sprocket end of the soundhead,

Fig. 6 is a horizontal the interior construction of the the projector mechanism, and of section through the mechanism at the axis of the drive motor,

Fig. 7 shows the upper portion of the with the cover plate removed,

view but Fig. 8 shows the cover plate as removed from' Fig. '7 and shows the remainder of the mechanism of Fig. '7, this view being inverted in relation to Fig. 7 in order that the relation of the parts may be more apparent,

Fig. 9 shows a modified ioi'm of film gate; and

Figs. l0, l1 and 12 Fig. 13 sound-.reproducer, general to Fig. 4.

Fig. 14 shows- The film with which show details thereof, v shows a view of a modified form of the view corresponding in the pressure roller.

this projector is intended to cooperate is of the conventional 16mm. width and is provided with pictures of exactly the same size as are ordinarily used film. The main difference teur film is that one on 16 mm. amateur from the usual amarow of sprocket holes is omitted and a sound-track preferably of the variable area type and of an inch in width approximately 6/ 100ths is located approximately where the row of sprocket holes would have been.

Other differences are run at a speed oi 24 that the film is made to frames or pictures per second which is the usual speed in talking motion pictures instead of 16 pictures per second which has heretofore been usual in 16 mm. films.

The

reason for this is that such pictures can be properly printed by projection when desired from standard theatre films or the equivalent without requiring that a special negative be taken and a special sound-track be made to be capable of reproduction in this apparatus.

The projector as shown in Fig. l is housed within a carrying case 10. This carrying case as indicated at H is lined withappropriate soundabsorbing material to absorb any noise which might be produced by the projector mechanism, the motor, or the fluttering of the film in order to avoid any disturbance of the audience, and is provided with suitable apertures for the lens as at l2, for the entrance and exit of wires as at l3,

and for the entrance and exit of the film as at H.

The case is also provided with ventilation apertures 90 in the front, back, and lid, and with a door 9| at the back which provides accessto the amplifier tubes without removing the machine from its case. The front of the case opens downwardly to provide easy access to the film side of the machine for threading, etc.

Upon the outsi' e of the carrying case are detachably mounted the film reel arms i 5, a reel on the lowermost arm being driven by the belt I 6 which passes over the rollers ll.

The loudspeaker cableis plugged into the base of the machine as indicated at 209, and when the case is closed and in operating condition passes out through the aperture I3.

After the film has been threaded with the case open, the case is closed and remains in closed position during operation, thereby retaining within the case not only the noise of the projector but also any stray light which may escape from the lamphouse.

The case is provided with a suitable leveling mechanism which may, .for example, Be a vertically slidable memberretained by the set screw l8 or the member I8 may itself directly control an appropriate member for raising or lowering the front end of the case.

The projector and attendant mechanism are mounted upon a base 20. This base is preferably made from a bent sheet of metal and carries upon it the amplifier and photocell in a manner analogous to that customary in the manufacture of radio sets. It also carries the projector and soundhead mechanism.

.The projector and soundhead mechanism will be first described in detail and thereafter the related electrical mechanism will be described.

Upon the'base 20 is mounted an auxiliary base 2| which is made in the form of a casting securely attached to the base 20, and carries the soundhead mechanism and the motor 22.

This motor 22 is an essential'portion of the projector mechanism, for it carries within its housing at one end the entire drive mechanism and bearings for the sprockets, and at the other end the intermittent feed and framing mechanism; it likewise serves to support at its side the picture lamphouse and attendant optical system, and at the front there are built into the motor housing the film guides and lens mount. This motor includes a rotor 23 (Fig. 6) mounted within the stator structure 22 which is carried in the us'ualcentral casing, but in place of the usual end-bells are substituted special housings provided with appropriate bearings, etc. forthe rest of the mechanism. The end-bell 30 at the each of these shafts is mounted a gear as indioated upon the shaft 32 at 33 in Figs. 5 and 6. Both of these gears are driven by a gear 34 which is out upon one end of the rotor shaft 34. Immediately adjacent the other end of the rotor with the cam mechanism of the intermittent feed and. with the shutter 4|.

The intermittent feed is of the claw type and is best shown in Figs. 6, '7 and 8. The member 42 extends from the shaft 43 on which it is vertically slidable to and fro through the slot 44 which is beneath the aperture 45. This member 42 carries at its end and extending through the slot 44 claws which are adapted to engage and move the film. At its other end, this member bears the arm 46 extending outwardly into the casing and adapted to slide longitudinally along the pin 41 which is rigidly attached to the arm 48. A pin 49 cooperates with the aperture 50 in the member 42 to impart a vertical movement of the claw and this pin 49 is carried by the member 5| which is pivoted at 52 to the adjustable arm 53.

The arm 5| is provided with an aperture having parallel top and bottom within which the cam 54 is adapted to operate in order to move this arm and with it the feed claw vertically.

Framing is a'ccomplishedby moving the eccentric pivot 55 about its axis by means of the knob which is integral with this pivot member.

The in-and-out movement of the feed claw is accomplished by means of the cam 56 which acts upon member 48 and which, in turn, through its cooperation with the members 41 and 46 causes rotation of the member 42 about the shaft 43.

It will thus be apparent that the claw member 42 is moved up and down a predetermined distance and also moves in-and-out of the sprocket holes at the proper time and that adjustment of the position thereof at the times when the various phases of the movement will occur is readily affected by means of the eccentric 55.

It will be apparent from Figs. 6 and 8 that some portions of the mechanism just described are mounted upon the cover plate 51 while other portions are mounted upon the end-bell of the motor 58, but that these parts are so related that the unit may be easily assembled,

. One form of film gate is shown in Figs. 3 and 6.

in the form of a pressed metal plate having ap-.

propriately-formed contact surfaces for the film and having outwardly extending ears at the top and bottom, as shown, by which it may be grasped to open it. This gate is held in closed position .by the springs 6| against the pressure of which it may be opened by grasping the ears above referred to and the elongated apertures in the sides of the gate which engage the pins 62 may then be slid down over the pins 52, retaining the gate in open position.

A modified form of gate is shown in Fig. '9 and this particular form of gate is found to be peculiarly effective when the film is drawn by traction tubes, which must operate at a relatively low of the'intermittent feed on sprocket holes on one edge of the film only.

In this gate a backing plate 59 is provided as in the gate previously referred to, but the film is pressed toward this by a linear shoe 10. This shoe is provided with ears II which-serve the same function as the ears above referred to and these cars are each provided with a notch 12 in their lower edges whereby the pressure shoe may be maintained in open position by drawing it outwardly and hooking these notches over the plates 13, which also serve as spring-retaining members.

The opposite edge of the film is prevented from fluttering by a. guide I I which extends the entire length of the gate but which, instead of being pressed firmly against the film by springs, is set at such spacing from the guide on the backing plate that the film can move freely therebetween;

This avoids producing any tension on the edge of the film which is not drawn by the intermittent and at the same time, dueto the small clearance (which may be of the order of two one-thousandths of an inch) and acting in cooperation with the pressure shoe at the other edge of the aperture, prevents any flutter of the film at the projection aperture.

The guide 14 is spring-pressed toward the shoe 59 but is stopped by eccentric headed screws I5 mounted at the top and bottom of the gate. This permits the shoe I0 to rise when a splice or other thickened portion of the film passes through the gate and at the same time provides a clearance between the shoe and the film under normal operating conditions.

In order to permit the film to be readily threaded through the apparatus, a bar 16 is rigidly attached to the shoe I0 and operates in a slot in the shoe I4. When the shoe I0 is retracted by means of the ears II, the bars I8 which are pro- .vided at both the top and bottom of the gate likewise retract the shoe 14 since the movement of the shoe I0 is greater than the length of the slots in the shoe I4, but when the shoe I0 is released and permitted to ride against the surface of the film, the pins 18 move forwardly in the slots when the shoe 14 contacts with the eccentric headed screw I5 and neither of the shoes therefore interferes with the normal operation of the other.

The film is illuminated at the aperture by means of a light of the usual incandescent type diagrammatically indicated at 80, behind which is adjustably mounted a reflector 8| which is spaced from the lamp housing 82 by the screws 83, and is retracted against these screws 83 by the screw 80, there being three of the screws 83 as will be seen from Figs. 3 and 6 considered together.

In front of the lamp-housing 82 is mounted the condenser lens barrel 85 which contains the usual condenser lenses 8G and is maintained in proper adjustment by the set screw 81, all as shown in Fig. 6. i

The top of the lamp-house is providedwith a ventilating-flue 82 which serves to direct heated air from the lamp-house upwardly through openings in the lid of the case. These openings are so positioned as to be immediately over the top of the flue 82 when the case is closed.

The cooling air is admitted through the other ventilating openings 90 in the front and back of the case. It will be apparent that on account of the larger number of openings most of the air enters around the amplifier tubes in the rear of the case and serves to first cool the amplifier temperature, and then passes to the bottom of the lamp-house and, passing upwardly therethrough serves to cool the projection lamp which operates at a higher temperature. A minimum quantity of air is accordingly required to adequately perform both cooling functions, and the structure is thus simplified. Further, the, heat of the projection lamp itself provides sufficient draft to sumciently cool both the lamp and the amplifier tubes.

It will be seen from Fig. 3 that the film passes over the top of sprocket 31 which draws the film from the upper or let-off reel and then passes in the form of a fiat loop to the top of the gate 58 through which it is drawn by the intermittent feed mechanism already described and from which it passes in the form of another loop to the sound reproducing mechanism, which will be next described, and from thence it passes up to the sprocket 38, and then through another loop to the bottom of the sprocket 31 which serves as a hold-back sprocket for thelower reel.

The sound reproducing system, Fig. 4, is of the usual photoelectric type including a photoelectric cell, an exciter lamp, an optical system, and means for drawing the film through between the optical system and the photoelectric cell.

The exclter lamp of the present sound reproducer is indicated at I00 and is mounted within an adjustable socket within the casing IN. The light from this lamp passes through the optical system indicated generally at I02 which will be described in more detail later, and is focussed thereby upon the sound-track of the film which is carried on the surface of the drum I03, with the sound-track overhanging the inner edge of the drum. After passing through the film, the light strikes the reflecting surface I04 whence it is reflected through the aperture I05 to the photoelectric cell 200 located within the member 2|. The film is held against the drum I03 by an idler I06 which maintains the film firmly in engagement with the drum at this point. After passing around the drum for a sufficient distance .1

to give good frictional contact, the film passes over the roller I01 and then around the roller I08, which latter roller is mounted on a shaft carrying at its other end the flywheel I09, and from this roller I08 the film then passes up over the sprocket 38 as before described.

The roller I08 is preferably sandblasted on its outer surface in order to provide adequate frictional contact within the small area. The action of the flywheel serves to prevent any irregularities being introduced into the motion of the film, whence the entire sound reproducing unit will operate in a uniform manner without any fiut tering or variation in film speed.

The drum I03 is rotatable upon a shaft III) as shown in Fig. 4. The interior of this drum is hollowed out and provided with a fiat frictionsurface III. able pressure shoes II! of which there may be three or more and which are preferably made of some such composition as oiled felt or leather, are pressed by the springs H3. It will be seen that the friction means III cooperating with the surface III produce a uniform braking action Against this friction surface suit- I axis, as would be the case to a certain extent if there were no braking or damping action.

The optical system generally indicated at I02 consists of a cylindrical lens I20 of fairly large diameter and having its axis vertical, i. e., parallel with the direction of the movement of the film and with the longitudinal axis of the soundtrack, and of such focal length that light from the lamp I00 is focussed within the lens I2I.

This lens I2I is likewise a cylindrical lens but is of very short focal length, the focal length in fact being so short that the errors normally existingin such a lens are negligible. The focal length of this lens is iurther so related to the vertical diameter of the luminous element of the lamp I00 that a linear image having the pro-per width will be formed transversely of the soundtrack.

This lens I2I may be seated in a small depression in the face of the casing of the system and upon it rests the member I22 which member has a U-shape longitudinally, but with'a deshaped memberhave a spacing the same as the axial dimension of the lens I20 which is rendered parallel on the ends and'have a depression to cooperate with the curved surface thereof, and the member I22 thereby maintains these two lenses accurately in perpendicular relation -to each other. The member I22 passes through a slot in the member I23 and the lens I20 also passes through this slot and rests with its opti- 'cally-surfaced portion against the ends of the slot.

The end of the member I23, which projects as illustrated, cooperates with a slot or keyway in the bracket I24 which is made integral with the I member 2 I. It will be apparent that the surfaces of the lens I20 and therefore also the'surfaces of the lens I2I will be maintained in a perma nent alignment with relation to the frame of the machine, and if the keyway is properly positioned .With relation to the longitudinal axis of the film,

the line'image above referred to will be accurately positioned transversely of the sound-track.

From the sound-track the light, of course, again diverges and it then strikes thereflecting surface I04 and, as before described, passes through the aperture I05 to the photocell which is mounted interiorly of the base 2|.

The flange I28 of the pressure-roll I00 is fixed, whereas the flange I 29 is pressed against the film by a spring, thereby holding the-sound-track edge of the film firmly against the flange I20 and accurately fixing the location of the sound-track in relation to the reproducer.

In the modified form of sound reproducer shown in Fig. 13, parts similar to those in Fig. 4 are indicated by similar reference numerals, while modified elements are indicated by primes'i The major modification in this form is the reversed mounting of the friction elements.

- The friction plungers I I2 are carried by the drum I03 and rotate therewith; while the friction surface III' is in the form of a washer, pinned to the base-member 2I to prevent rotation, and mounted co-axially on the shaft H0.

The cover member I03a which holds the springs H3 in place is held by a snap-ring 3' which replaces the screws shown in Fig. 4.

A somewhat more compact form of optical system is shown at I02, but this is, in generaL'similar to that of Fig. 4 and needs no further description. The member I23 is made integral with the casing I02, but performs the same function' as the member I23. The reflecting surface I04 differs in that it is a flat plate instead of a solid metallic prism, but is identical in function and operation with the construction of Fig.4. This provides a construction which is in principle similar to that of Fig. 4, but which is somewhat more convenient to manufacture.

The photocell 200, being rather sensitive to jars and vibration, is mounted on an appropriately cushioned socket, and in the present case it is preferable to do this by a spring mounting underneath the base of the apparatus, the spring mounting carrying the rods 20I supporting the photocell socket and also the socket for the amplifying tube 224 which is the first amplifier tube following the photocell and is preferably of the screen-grid type. This integral mounting of the photocell and amplifier tube prevents relative oscillation of the grid lead to the said tube and associated parts which might produce undesir at the same time electrically and magnetically shielding both the photocell and high-gain amplifying tube.

The power transformer "is located at 206 and feeds a rectifier tube indicated at 280 for supplying plate current for the amplifier tubes, which is filtered through the condenser 202 and an appropriate choke which, in the present instance, is also used as the field magnet of the dynamic speaker. The remainder of the amplifier tubes are mounted along the back edge of the base, the sockets being attached to the lower section of the base and all of the wiring being contained thereunder. 1

The socket 208 at the front of the base in Fig. 1 is adapted to receive the loudspeaker plug 209.

The exciter lamp is operated either by alter-v nating current supply through the power transformer or, preferably, by a high frequency oscillating current supplied by an oscillator tube which fore described, is transmitted through the film to the photocell 525. r

The volume is controlled by the knob 302, Fig. 1, of the photocell 525 by means of the potentiometer 520 and the tone can be varied by operation of the switch SSS-which .serves to short-circuit the condenser 539. I

The apparatus" described is not only compact and portable but produces a quality of picture and sound reproduction comparable with that of the large and expensive equipment using standard film.

I claim:

1. Drum mechanism for carrying a sound record film past a reproduction point comprising a shaft, a drum rotatably mounted upon said shaft and adapted to be driven by the film passing thereover, an annular means having a smooth bearing face and fixed to one of the aforesaid parts, and a plurality of spring-pressed plungers I rotationally amxed to the other of the aforesaid parts to provide a braking force upon said drum, whereby said drumoperates at a uniform speed.

2. Drum mechanism for carrying a sound record film past a reproduction point comprising a shaft, a drum rotatably mounted upon said shaft and adapted to be driven by the film passing thereover, an annular recess in said drum having a smooth bottom face, and a plurality of springpressed plungers co-operating with said bottom face to provide a braking force upon said drum, whereby said drum operates at a uniform speed.

3. Drum mechanism for carrying a sound record film past a reproduction point comprising a shaft, a drum rotatably mounted upon said shaft and adapted to be driven by the film passing thereover, an annular member mounted coaxially with the shaft and having a smooth face toward the said drum, and a plurality of springpressed plungers mounted in the said drum and co-operating with the said face to provide a braking force upon said drum, whereby said drum operates at a uniform speed.

4. Drum mechanism for carrying a sound record film past a reproduction point comprising a shaft, a drum rotatably mounted upon saidshaft and adapted to be driven by the film passing thereover, an annular member mounted co-axially with the shaft and having a smooth face toward said film and a plurality of spring-pressed plungers mounted in the said drum and co-operating with said smooth face to provide a braking force upon said drum, said plungers having faces of a yieldable material, whereby said drum operates at a uniform speed.

5. Drum mechanism for carrying a sound record film past a reproduction point comprising a base member, a shaft carried by said base member, a drum rotatably mounted upon said shaft and adapted to be driven by the film passing thereover, an annular member mounted upon said shaft at one sideof said drum and having a smooth surface facing toward the said drum,

the said annular member being secured against rotation, and a plurality of spring-pressed plungers mounted for axial movement in the drum and cooperating with said smooth face to provide a braking force upon said drum whereby said drum operates at a uniform speed.

6. Drum mechanism for carrying a sound record film past a reproduction point comprising a shaft, a drum rotatably mounted upon said shaft and adapted to be driven by the film passing thereover, an annular recess in said drum having a smooth bottom face, and a plurality of springpressed plungers cooperating with said bottom face to provide a braking force upon said drum, said plungers being faced with a yieldable material, whereby said drum operates at a uniform speed.

'7. Drum mechanism for carrying a sound record film past a reproduction point comprising a base member, a shaft carried by said base member, a drum rotatably mounted upon said shaft and adapted to be driven by the film passing thereover, an annular recess in said drum having a smooth bottom face, and a plurality of springpressed plungers mounted for axial movement in the base member and cooperating with said bottom face to provide a braking force upon said drum, whereby said drum operates at a uniform speed.

8. In sound reproducing apparatus, a drum adapted to carry film having a sound record thereon past a reproduction point with the sound record portion of said film overhanging the edge of said drum, and means for maintaining the said film in a uniform position laterally of the said drum, said means comprising a flanged roller pressing the said film against the drum, one of said flanges being fixed to the said roller and the other of said flanges being spring-pressed toward the first flange.

9. In sound reproducing apparatus, a drum adapted to carry film having a sound record thereon past a reproduction point with the sound record portion of said film overhanging the edge of said drum. and means for maintaining the said film in a uniform position laterally of the said drum, said means comprising a flanged roller pressing the said film against the drum, the flange on the sound-track end of said roller being fixed to the roller for accurately determining the position of that edge of the film and the other of said flanges being spring-pressed toward the first flange for maintaining the film in uniform contact with said first flange.

HAROLD C. HOLDEN. 

